<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
	</head>
	<body>
		<script type="text/javascript">
		var a =2; b=3;
		var n ='2a'; m ='5b';
		var x =false; y =true;
		console.log(a+b); 	//5
		console.log(a+n);	//22
		console.log(a-b+n);	//-12a
		console.log(a+b+x);	//5
		console.log(b+m+y);	//35btrue
		console.log(a-b+x+y-n+m);	//NAN5b
		
		//作业2
		var c = prompt("请输入用户工资","3000")
		console.log("你的工资是；", c)
		console.log(typeof c)
		
		//作业3
		var a = prompt("请输入一个有效的年份")
			b = a / 400
		console.log(b,"整数是闰年，浮点数则不是")
		
		//作业4
		var f = prompt("请输入用户工资")
			if (f >= 20000){
				alert("高工资")
			}else if (f >= 8000 || f < 20000){
				alert("中高工资")
			}else{
				alert("普通工资")
			}
		// 作业4
		var kg = prompt("请输入你的体重")
			m = prompt("请输入你的身高")
			s = kg / m 
			if (s > 20 || s < 25){
				alert("正常")
			}else {
				alert("你个垃圾")
			}
			
		
		</script>
	</body>
</html>
